Batting trainer apparatus and method

ABSTRACT

A cup for holding a ball is equipped on its underside with a necked plunger that extends downwardly and may engage a latch remotely operable by a treadle and fastened to the base of an annular housing. Planar spring means between the cup and the housing catapults the ball into the air when the plunger is released.

United States Patent 72] Inventor Norman J. Van Skyhawk Salt Lake City,Utah [21] Appl. No. 868,776

[22] Filed Oct. 23, 1969 [45] Patented Dec. 14, 1 971 [73] AssigneeHarmon Killebrew Enterprises, Inc.

Salt Lake City, Utah [54] BATTING TRAINER APPARATUS AND METHOD 19Claims, 18 Drawing Figs.

[52] US. Cl 273/26 R, 124/16,124/34,124/41, 273/D1G. 12 [51 Int. Cl A63b69/40 [50] Field of Search 273/26 R,

[56] References Cited UNITED STATES PATENTS Re.9,042 1/1880 Paine 124/172,891,795 6/1959 Glintz... 124/16 X 3,261,340 7/1966 Laird 124/41 X299,436 5/1884 Stockman 124/37 X Primary Examiner-Richard C. PinkhamAssistant Examiner-Theatrice Brown Artorney- Lynn G. Foster ABSTRACT: Acup for holding a ball is equipped on its under side with a neckedplunger that extends downwardly and may engage a latch remotely operableby a treadle and fastened to the base of an annular housing. Planarspring means between the cup and the housing catapults the ball into theair when the plunger is released.

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SHEET 1 [IF 4 INVENTOR. NORMAN J. VAN SKYHAWK BY N ATTRNEY PATENTED DEC]41971 SHEET 2 [IF 4 INVENTOR. NORMAN J. VAN SKYHAWK BY: g

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INVENTOR. NORMAN J. VAN SKYHAWK ATT RNEY PATENTEB DEC! 4|s1| SHEET [1F 4IN VENTOR.

m m GE 8m NORMAN J. VAN SKYHAWK A TORNEY BATTING TRAINER APPARATUS ANDMETHOD BACKGROUND OF THE INVENTION 1. Field of Invention This inventionrelates generally to spring-loaded throwing devices; and, moreparticularly to such apparatus adapted for baseball-batting practice andoperable by the unassisted user.

2. Description of the Prior Art Some of the operations in the game ofbaseball, e.g., batting the ball, require greater skill and coordinationthan is ordinarily possessed by small boys learning the game. Hence,extensive individual practice to develop such a skill tends to make thegame more enjoyable when the learner participates as a team member. Thepresent invention is directed toward providing intensive battingpractice without aid from others.

Disadvantages of other throwing devices have been their excessive bulk,weight and complexity, making them difficult for the young user tooperate successfully.

OBJECTS AND SUMMARY OF THE INVENTION Objects of the present inventionare to provide a ball-tossing device that is easily portable, reliableand simple to operate. Important features of the invention are itssimple, rugged construction and an absence of delicate parts and theneed for high precision in manufacture. Another important feature isthat it is completely safe for use by a young child, being madeprimarily of synthetic plastic having natural resilience and no sharpedges.

A cup having a necked plunger projecting downwardly from it is centrallysupported in an annular housing by a planar resilient biasing means. Theplunger may be engaged by a latch when the cup is pressed downwardly. Aball may then be placed in the cup and the latch released by a foottreadle attached thereto, whereupon the ball is tossed vertically intothe air.

These and other objects and features of the present invention willbecome more fully apparent from the following description and appendedclaims taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of theinvention illustrating the simple means of spring loading the ejectioncup thereof;

FIG. 2 is a similar view showing the spring means applied and ready forrelease;

FIG. 3 is a similar view including a human figure to show how theinvention is operated to release the ball-broken lines show the ejectedball and the moved foot of the operator;

FIG. 4 is an exploded view to show all of the parts of the in I FIG. 11is a sectional view of a modified plunger receptacle;

FIG. 12 is a sectional view of a modified plunger;

FIG. 13 is a top view of the base and a modified latch;

FIG. 14 is a sectional view of a second modification of the plungerreceptacle;

FIGS. l18 comprise a series of four sectional views to illustrate atoggle that may be incorporated into the actuation arm; and

FIGS. B-B, C-C and D-D are sections taken on cutting lines so labeled inFIG. l3.

DESCRIPTION OF THE PREFERRED EMBODIMENTS As is best shown in FIGS. 4, 7and 8, the invention consists essentially of an enclosure or housing 20,a resilient biasing means 22, a latch means 24 for centrally latchingthe resilient biasing means to the base 26 of the housing 20, and alatch release means 28.

The housing 20 has two primary parts. The base 30 has outwardly slopingsidewalls 32, terminating in an annular flange 34 that extendsoutwardly. The top member 36 has an annular flange 38 that coincideswith that of the base and is fixed thereto. The sidewalls 40 extendupwardly from the flange 38 and terminate in an annular top 42, that iscurled downwardly for esthetic appearance. A shelf 44 is provided by aninverted, annular channel 46 that is fixed inside the top member 36. Theshelf 44, being spaced slightly below the curled-down edge of theannular top 42, provides retaining means for peripheral retention of theresilient biasing means 22.

The resilient biasing means 22 in this preferred embodiment, is a spidersupport 48 having a central portion 50 and a plurality of radial spokes52 integral therewith. The spider support 48 is preferably made of somesynthetic plastic with natural springiness, or memory, such aspolypropylene. An ejection cup 54 is fixed to the top of the centralportion 50 of the spider support 48, for supporting and ejecting a ball56, as shown in FIGS. I, 2, 3, 5 and 6. This ejection cup 54 may eitherbe molded on the top of the central portion 50 of the spider support 48,as an integral part thereof as shown in FIG. 9, or it may beincorporated as a part of the latching means as shown in FIGS. 4, 8 and12.

The latch means 24, best shown in FIGS. 4 and 8, has a downwardlyextending, necked plunger 58, centrally fixed to the underside of thespider support 48. A preferred means of fastening the plunger 58 to thespider support 48 is by means of a single screw 60, that also passesthrough the ejection cup 54. Alternatively, the ejection cup 54 may beintegral with the plunger 58, as shown in FIG. 12. A tubular plungerreceptacle 62 is centrally fixed to the base 26 by a rivet 64, or byother suitable means. A downwardly pointing, conical surface 66 on theplunger 58 and an upwardly divergent, conical inner surface 68 at theupper end portion of the receptacle 62 comprise a guide means for makingthe plunger and the receptacle easily engageable without the necessityof high precision in the manufacture of the parts. A latch member 70,having a hole 72 to admit passage of the plunger 58, is slidably engagedin a slot 74 in the receptacle 62, and is biased toward one side of theenclosure 20 by a tension spring 76. A stop in the form of a shoulder 78allows the hole 72 of the latch member 70 to become sufiicientlymisaligned with the tubular receptacle 62 that it may engage the neck 80of the plunger 58, when the plunger is forced into the receptacle 62.

The latch release means 28 has a long, flat guide arm 82 fixed to thebase 30 and extending outwardly therefrom. A preferred construction forthe guide arm 82 is shown in FIG. B-B; the edges 820 are flangeddownwardly for strength. A long, flat actuation arm 84 is fastenedparallel to the guide arm 82 for limited, longitudinal sliding movementrelative to the guide arm 82. The fastening means shown in most of theFigures are flanged studs 86 fixed to the guide arm 82 and extendingthrough slots 88 in the actuation arm 84. The flanges 90 of the studsare of larger diameter than the widths of the slots 88 so that the twoarms may not become disengaged. An alternative means of fastening theseanns together is shown in FIG. 10. C"-clamps pass over the actuation arm84 and engage recesses in the underside of the guide arm 82 by springtension. An upwardly arched treadle 92 is hinged at one end to the outerend of the guide arm 82, and at its other end to the outer end of theactuation arm 84. These hinged connections are achieved simply bynarrowing the thickness of the material from which the arms are made, atselected points. The inner end of the actuation arm 84 is equipped witha spring clamp 94 that may releaseably engage the latch member 70 bygrasping a stud or other fixture thereon. Alternatively, the springclamp may be in the form of a continuous, necked spring loop 94' thatsurrounds a stud on the latch member 70 (see FIGS. 13 and CC).

A simplified construction, wherein the latch member 70' is integral withthe end of the actuation arm 84 is shown in FIG. 14. A stop 85 isincluded to limit motion of the latch member 70.

In practicing the invention, the user first places a ball 56 on theejection cup 54 and exerts pressure sufficient to latch the plunger 58into the receptacle 62. This places the spider support 48 under springtension so that it will forcefully eject the ball upon release of theplunger 58. The user than places his foot on the treadle 92 and deformsit to a flattened shaper with downward pressure, causing the actuationarm 84 to move forward and grasp the latch member 70. In the embodimentwherein the actuation arm 84 is equipped with a necked'spring loop thatsurrounds a stud on the latch member, the neck of the loop 94' must passbeyond the stud. When the user is ready to strike the ball, he removeshis foot from the treadle 92 and typically places it astride thereof.The actuation arm 84, being spring biased toward the treadle 92 both bya spring 96 and by the springiness or memory of the treadle itself,moves toward the treadle 92. This in turn moves the latch member 70 fora distance sufficient to release the plunger 58 and eject the ball 56.

The force with which the ball is ejected may be regulated by means of anadjustable plunger, such as that shown in FIG. 12, wherein the plunger58' is threadedly engaged in a boss 98 in the spider support 48.Adjustment of the necked portion 80 of the plunger 58 relative to thelatch member 70 enables the user to select the amount of spring tensionthat will be on the spider support when it is latched to the base. Thesame result may be achieved with an adjustable plunger receptacle 62, asshown in FIG. 11, wherein the latch member 70 may be moved relative tothe necked portion of the plunger 58. Adjustable spring tension of thespider support may also be achieved by the adjustment of both anadjustable plunger and an adjustable receptacle relative to one another.

An important feature of the invention is that a predetermined time delayallows the user to shift his weight and prepare his bat before the ballis ejected. This is due to the fact that a specified amount of time isrequired for the plastic treadle to resume its normal shape after havingbeen deformed by the user's foot. Polypropylene has been found to be asatisfactory material for making a treadle that will achieve thisresult.

It is also important to note the rather remarkable features of thespider support. It performs simultaneously the functions of providingspring means for ejecting the ball, and of serving as a support for theejection cup and the plunger. It is easily removable to provide easyaccess to the latching mechanism. It is completely safe for young usersto handle; and, being loosely retained in the housing 20, it requires noprecision of manufacture.

FIGS. 15-18 illustrate the action of a toggle line 97 that may beincorporated into the actuation arm 84". It is formed by a wedge-shapedrecess 95 in the top surface of the actuation arm 84" that defines oneend of the toggle link 97 and a similar recess 93 in the bottom surfaceof the actuation arm 84 that defines the other end. Forward motion ofthe actuation arm 84 causes the toggle link 97 to fold under or over theportion of the actuation arm adjoining the treadle (depending on therelative locations of upper-surface and lower-surface recesses). Thiseffectively shortens the length of the actuation arm 84" by twice thelength of the toggle link 97. A dog 91, pivotally supported above thefolded toggle link 97 by a support 89 attached to the base 30, maintainsthe resulting three thicknesses of the actuation arm 84" in intimatecontact, so that the toggle link 97 may not unfold itself as theactuation arm 84" is withdrawn. Use of this link may obviate the needfor an assisting spring to bias the actuation arm 84" toward the treadle92 after it has been flattened.

The invention may be embodied in other specific fonns without departingfrom the spirit of essential characteristics thereof. The presentembodiments are, therefore, to be considered in all respects asillustrative and not restrictive, the scope of the invention beingindicated by the appended claims rather than by the foregoingdescription, and all changes which come within the meaning and range ofequivalency of the claims are therefore to be embraced therein.

What is claimed and desired to be secured by United States LettersPatent is:

1. Apparatus for tossing a ball vertically into the air to developcoordination between the stride and swing of a batter, comprising:

base means; resilient biasing means substantially planar in an at restposition and disposed generally parallel to the base means, the biasingmeans comprising means for carrying the ball;

support means carried by the base means for supporting the biasing meansat the peripheral edges of the biasing means. in spaced relation abovethe base means;

first latch means mounted to the base means and mating latch meansmounted on the underside of the biasing means for releasably attachingthe biasing means to the base means when the biasing means are displaceddownward counter to the bias; and

release means comprising a treadle operable by removal therefrom of thefoot of a user for releasing the first and mating latch means fromlatched relation to allow the biasing means to move under force of thebias toward the at rest position thereby propelling the ball upwardly.

2. Apparatus as defined in claim 1 wherein the resilient biasing meanscomprise yieldable spider support means having a central portion andintegral radially directed spokes, the spider support means being formedof synthetic material with memory so that it resumes its planar at restposition upon being released from its deformed latched position.

3. Apparatus as defined in claim 1 wherein the ball-carrying meanscomprises an ejection cup adjustably connected near the geometric centerof the biasing means.

4. Apparatus as defined in claim 1 wherein the ball-carrying means andthe mating latch means are of one-piece construction and wherein themating latch means comprises a downwardly directed plunger.

5. Apparatus as defined in claim 4 wherein the first latch meanscomprises a vertically disposed receptacle having a cylindricalvertically oriented plunger-receiving bore, the receptacle being mountedto the base and having a generally horizontal slot which intersects thebore and a latching member slidably disposed in the slot in thereceptacle and having an aperture therein to admit passage of theplunger, the latching member being biased laterally partially out ofalignment with the bore in the receptacle so as to engage a steppedrecessed neck of the plunger when the plunger has been displaced throughthe aperture against the bias of the biasing means.

6. Apparatus as defined in claim 5 wherein the vertical position of thelatching member is adjustable.

7. Apparatus as defined in claim 4 wherein the length of the plungerbelow the biasing means is adjustable.

8. Apparatus as defined in claim 1 wherein the release means comprise aguide ann fixed to the base means and extending radially outwardlytherefrom; an actuating arm hingedly connected to the guide arm at theend of the guide arm remote from the base means and superimposed overthe guide arm for longitudinal sliding movement relative thereto, theactuating arm being spaced above the guide arm adjacent the hingeconnection so as to form a downwardly displaceable treadle, andreleaseable coupling means carried by the end of the actuating armproximal to the base means capable of free: ing the attachment betweenthe first and mating latch means when the treadle is released.

9. Apparatus as defined in claim 8 wherein the releasable coupling meansis a spring-biased clamp releaseably engaging a mating clamp mounted onthe first latching means with forward motion of the actuating arm, theclamp laterally displacing the first latching means out of latchingrelation with the mating latching means with rearward motion of theactuating arm and releasing the mating clamp at a predetermineddisplaced location.

10. Apparatus as defined in claim 8 wherein the actuating arm is made ofa flat length of synthetic plastic material and comprises a toggle linkformed by a wedge-shaped recess in the top surface of the arm to defineone end of the toggle link and a second wedge-shaped recess in the undersurface of the arm to define the other end of the toggle link, wherebyforward motion of the arm causes the toggle link to fold upon itselfinto parallel relation with the actuating arm and effectively shortenthe length of the actuating arm; and a depending dog mounted uponsupport structure carried by the base and supported above the foldedtoggle length, the dog pivotally displaceable from the vertical to thehorizontal in one direction to accommodate folding of the link andresisting pivotal displacement from the vertical to the horizontal inthe opposite direction to thereby maintain the resulting folded link inthe folded condition until the actuating arm moves rearward when thetreadle is released. I

11. Apparatus as defined in claim 8 wherein the actuating arm is formedof synthetic material with memory so that deformation thereof bydownward pressure causes lateral movement of the actuating arm relativeto the guide arm and the memory of the forming material causes thetreadle to resume the at rest spaced relation of the guide arm when thedownward pressure is removed from the actuating arm.

12. Apparatus as defined in claim 11 wherein the guide arm comprisesupwardly projecting studs fixed to the guide arm and projecting throughelongated slots in the actuating arm, each stud having a diametrallyenlarged flange at the end exposed through the slot so that direction ofrelative movement of the guide and actuating arms is well defined and sothat the arms are not inadvertently disengaged.

13. Apparatus as defined in claim 11 further comprising generallyC-shaped brackets mounted upon the guide and actuating arms formaintaining the actuating arm in parallel relation with the guide arm,each bracket passing transversely over the actuating arm and the ends ofthe bracket engaging the underside ofthe guide arm.

14. Apparatus as defined in claim 14 wherein the memory of the formingmaterial is slow acting so as to provide a time delay between release ofthe treadle and the freeing of the attachment between the first andmating latch means.

15. Apparatus as defined in claim 14 wherein the first latching means isequipped with a generally vertically oriented stud, and the proximal endof the actuating arm comprises an elongated spring loop disposed overthe stud and accommodating relative movement of the actuating and guidearms for the length of the loop whereupon the end of the loop engagesthe stud and moves the first latching member to release the biasingmeans thereby providing a time delay between actuation by the foot ofthe user and the release of the mating latch means.

16. Apparatus as defined in claim 11 wherein said synthetic material ispolypropylene.

17. A baseball skill developing and conditioning device comprising:

a base member having an annular wall defining an annular opening;

a hollow plunger-receiving sleeve mounted upon the base in axialalignment with the opening, the sleeve comprising a transverse slot;

a laterally displaceable arm disposed in the slot, the arm having athrough-bore therein adapted, when in a selected lateral position, toalign with the hollow of the plunger-receiving sleeve and biasingstructure for biasing the aperture partially out of alignment with thehollow;

a foot-actuated treadle formed of resilient material with memoryextending radially from a position adjacent the plunger-receiving sleeveto a position remote from the base, the treadle comprising a lowermember, the adjacent end of which is connected to the base and an uppermember juxtaposed the lower member along a substantial portion of thelength thereof and longitudinally movable relative thereto, the uppermember being releasably associated with the displaceable arm andcomprising (a) a first set of hinged joints which, in the normalposition, elevate a portion of the remote end of the upper member sothat the upper member is longitudinally shifted toward the remote end ofthe treadle and in the foot depressed position, the elevated portion isflattened against the lower member so that the upper member islongitudinally shifted toward the adjacent end of the treadle and (b) asecond set of hinged joints near the adjacent end of the treadle;

one-way gate structure carried by the base which allows the second setof joints to fold a portion of the upper member upon itself in responseto flattening the elevated portion, the gate structure restraining theportion in the folded condition until the treadle longitudinally shiftsthe upper member toward the remote end of the treadle, the longitudinalshifting of the upper member causing simultaneous lateral displacementof the arm so that the throughbore therein is moved selectively into andout of alignment with the hollow of the plunger-receiving sleeve;

annular support structure carried upon the base and presenting anenlarged central aperture, exposing the central portion of the base andthe plunger-receiving sleeve;

a deformable resilient biasing member comprising a central portion andradially outwardly projecting fingers, the ends of which rest upon theannular support structure; and

a ball-receiving pedestal comprising a downwardly projecting plungerhaving an annular recess exposed adjacent a forwardly tapering headthereof, the plunger being adapted to project into the hollow of theplunger-receiving sleeve and through the bore in the laterallydisplaceable arm to be latched therein when the arm moves into theannular recess, the plunger having a variable length to selectively varythe deformation of the biasing structure when the plunger is latchedwithin the plunger-receiving sleeve so that the height to which the ballwill be projected can be selectively varied.

18 In a method of projecting a ball vertically into the air, the ballbeing carried upon a vertically displaceable upwardly biased pedestalhaving a downwardly directed plunger, the steps of:

biasing the ball-carrying pedestal toward a normal elevated position byuniformly distributing the biasing force radially around the pedestal;

forcing the ball-carrying pedestal downwardly against the bias;

locking the plunger in the downward-biased position;

longitudinally shifting an upper layer of a foot treadle relative to alower layer from an at rest to an active position by depressing anelevated portion of the upper layer with a foot preparatory to unlockingthe plunger; and

allowing the upper layer of the treadle to longitudinally shift to theat rest position to unlock the plunger by removing the foot from thetreadle thereby snapping the ball-carrying pedestal upwardly to its atrest position in response to the upward force of the bias.

19, [n a method as defined in claim 18 wherein the forcing step ispreceded by adjusting the effective length of the downwardly directedplunger thereby selecting the height to which the ball will beprojected.

l i l

1. Apparatus for tossing a ball vertically into the air to developcoordination between the stride and swing of a batter, comprising: basemeans; resilient biasing means substantially planar in an at restposition and disposed generally parallel to the base means, the biasingmeans comprising means for carrying the ball; support means carried bythe base means for supporting the biasing means at the peripheral edgesof the biasing means in spaced relation above the base means; firstlatch means mounted to the base means and mating latch means mounted onthe underside of the biasing means for releasably attaching the biasingmeans to the base means when the biasing means are displaced downwardcounter to the bias; and release means comprising a treadle operable byremoval therefrom of the foot of a user for releasing the first andmating latch means from latched relation to allow the biasing means tomove under force of the bias toward the at rest position therebypropelling the ball upwardly.
 2. Apparatus as defined in claim 1 whereinthe resilient biasing means comprise yieldable spider support meanshaving a central portion and integral radially directed spokes, thespider support means being formed of synthetic material with memory sothat it resumes its planar at rest position upon being released from itsdeformed latched position.
 3. Apparatus as defined in claim 1 whereinthe ball-carrying means comprises an ejection cup adjustably connectednear the geometric center of the biasing means.
 4. Apparatus as definedin claim 1 wherein the ball-carrying means and the mating latch meansare of one-piece construction and wherein the mating latch meanscomprises a downwardly directed plunger.
 5. Apparatus as defined inclaim 4 wherein the first latch means comprises a vertically disposedreceptacle having a cylindrical vertically oriented plunger-receivingbore, the receptacle being mounted to the base and having a generallyhorizontal slot which intersects the bore and a latching member slidablydisposed in the slot in the receptacle and having an aperture therein toadmit passage of the plunger, the latching member being biased laterallypartially out of alignment with the bore in the receptacle so as toengage a stepped recessed neck of the plunger when the plunger has beendisplaced through the aperture against the bias of the biasing means. 6.Apparatus as definEd in claim 5 wherein the vertical position of thelatching member is adjustable.
 7. Apparatus as defined in claim 4wherein the length of the plunger below the biasing means is adjustable.8. Apparatus as defined in claim 1 wherein the release means comprise aguide arm fixed to the base means and extending radially outwardlytherefrom; an actuating arm hingedly connected to the guide arm at theend of the guide arm remote from the base means and superimposed overthe guide arm for longitudinal sliding movement relative thereto, theactuating arm being spaced above the guide arm adjacent the hingeconnection so as to form a downwardly displaceable treadle, andreleasable coupling means carried by the end of the actuating armproximal to the base means capable of freeing the attachment between thefirst and mating latch means when the treadle is released.
 9. Apparatusas defined in claim 8 wherein the releasable coupling means is aspring-biased clamp releasably engaging a mating clamp mounted on thefirst latching means with forward motion of the actuating arm, the clamplaterally displacing the first latching means out of latching relationwith the mating latching means with rearward motion of the actuating armand releasing the mating clamp at a predetermined displaced location.10. Apparatus as defined in claim 8 wherein the actuating arm is made ofa flat length of synthetic plastic material and comprises a toggle linkformed by a wedge-shaped recess in the top surface of the arm to defineone end of the toggle link and a second wedge-shaped recess in the undersurface of the arm to define the other end of the toggle link, wherebyforward motion of the arm causes the toggle link to fold upon itselfinto parallel relation with the actuating arm and effectively shortenthe length of the actuating arm; and a depending dog mounted uponsupport structure carried by the base and supported above the foldedtoggle length, the dog pivotally displaceable from the vertical to thehorizontal in one direction to accommodate folding of the link andresisting pivotal displacement from the vertical to the horizontal inthe opposite direction to thereby maintain the resulting folded link inthe folded condition until the actuating arm moves rearward when thetreadle is released.
 11. Apparatus as defined in claim 8 wherein theactuating arm is formed of synthetic material with memory so thatdeformation thereof by downward pressure causes lateral movement of theactuating arm relative to the guide arm and the memory of the formingmaterial causes the treadle to resume the at rest spaced relation of theguide arm when the downward pressure is removed from the actuating arm.12. Apparatus as defined in claim 11 wherein the guide arm comprisesupwardly projecting studs fixed to the guide arm and projecting throughelongated slots in the actuating arm, each stud having a diametrallyenlarged flange at the end exposed through the slot so that direction ofrelative movement of the guide and actuating arms is well defined and sothat the arms are not inadvertently disengaged.
 13. Apparatus as definedin claim 11 further comprising generally C-shaped brackets mounted uponthe guide and actuating arms for maintaining the actuating arm inparallel relation with the guide arm, each bracket passing transverselyover the actuating arm and the ends of the bracket engaging theunderside of the guide arm.
 14. Apparatus as defined in claim 11 whereinthe memory of the forming material is slow acting so as to provide atime delay between release of the treadle and the freeing of theattachment between the first and mating latch means.
 15. Apparatus asdefined in claim 14 wherein the first latching means is equipped with agenerally vertically oriented stud, and the proximal end of theactuating arm comprises an elongated spring loop disposed over the studand accommodating relative movement of the actuating and guide arms forthe length of the loop whereupon the end of the loop engages the Studand moves the first latching member to release the biasing means therebyproviding a time delay between actuation by the foot of the user and therelease of the mating latch means.
 16. Apparatus as defined in claim 11wherein said synthetic material is polypropylene.
 17. A baseball skilldeveloping and conditioning device comprising: a base member having anannular wall defining an annular opening; a hollow plunger-receivingsleeve mounted upon the base in axial alignment with the opening, thesleeve comprising a transverse slot; a laterally displaceable armdisposed in the slot, the arm having a through-bore therein adapted,when in a selected lateral position, to align with the hollow of theplunger-receiving sleeve and biasing structure for biasing the aperturepartially out of alignment with the hollow; a foot-actuated treadleformed of resilient material with memory extending radially from aposition adjacent the plunger-receiving sleeve to a position remote fromthe base, the treadle comprising a lower member, the adjacent end ofwhich is connected to the base and an upper member juxtaposed the lowermember along a substantial portion of the length thereof andlongitudinally movable relative thereto, the upper member beingreleasably associated with the displaceable arm and comprising (a) afirst set of hinged joints which, in the normal position, elevate aportion of the remote end of the upper member so that the upper memberis longitudinally shifted toward the remote end of the treadle and inthe foot depressed position, the elevated portion is flattened againstthe lower member so that the upper member is longitudinally shiftedtoward the adjacent end of the treadle and (b) a second set of hingedjoints near the adjacent end of the treadle; one-way gate structurecarried by the base which allows the second set of joints to fold aportion of the upper member upon itself in response to flattening theelevated portion, the gate structure restraining the portion in thefolded condition until the treadle longitudinally shifts the uppermember toward the remote end of the treadle, the longitudinal shiftingof the upper member causing simultaneous lateral displacement of the armso that the through-bore therein is moved selectively into and out ofalignment with the hollow of the plunger-receiving sleeve; annularsupport structure carried upon the base and presenting an enlargedcentral aperture, exposing the central portion of the base and theplunger-receiving sleeve; a deformable resilient biasing membercomprising a central portion and radially outwardly projecting fingers,the ends of which rest upon the annular support structure; and aball-receiving pedestal comprising a downwardly projecting plungerhaving an annular recess exposed adjacent a forwardly tapering headthereof, the plunger being adapted to project into the hollow of theplunger-receiving sleeve and through the bore in the laterallydisplaceable arm to be latched therein when the arm moves into theannular recess, the plunger having a variable length to selectively varythe deformation of the biasing structure when the plunger is latchedwithin the plunger-receiving sleeve so that the height to which the ballwill be projected can be selectively varied.
 18. In a method ofprojecting a ball vertically into the air, the ball being carried upon avertically displaceable upwardly biased pedestal having a downwardlydirected plunger, the steps of: biasing the ball-carrying pedestaltoward a normal elevated position by uniformly distributing the biasingforce radially around the pedestal; forcing the ball-carrying pedestaldownwardly against the bias; locking the plunger in the downward-biasedposition; longitudinally shifting an upper layer of a foot treadlerelative to a lower layer from an at rest to an active position bydepressing an elevated portion of the upper layer with a footpreparatory to unlocking the plunger; and alLowing the upper layer ofthe treadle to longitudinally shift to the at rest position to unlockthe plunger by removing the foot from the treadle thereby snapping theball-carrying pedestal upwardly to its at rest position in response tothe upward force of the bias.
 19. In a method as defined in claim 18wherein the forcing step is preceded by adjusting the effective lengthof the downwardly directed plunger thereby selecting the height to whichthe ball will be projected.